In JP Publication of Application No. H04-361918, an article rearranging device is disclosed which has a carrying-in area as a receiving portion for receiving articles, and a retrieval area as a delivering portion from which the articles are taken out. It also has a transporting line which circulates through the carrying-in area and the retrieval area to transport articles, and a storage area having ten buffer lines which branch out from the transporting line and join the transporting line at a different location thereof.
In this article rearranging device, each of a plurality of articles to be transported is given one of double-digit identification numbers that are sequentially ordered in accordance with a specified order. However, the articles are handed over to the transporting line in the order in which operations on the articles are completed, regardless of the identification numbers. Thus, when the articles are received in the carrying-in area, the articles may be in an order different from the specified order.
In this article rearranging device, a primary sorting in which articles with the same ones digit are collected in the same buffer line is performed on the articles being transported by the transporting line. Once the primary sorting is completed, the articles are subsequently brought back into the transporting line in such an order that the articles in a buffer line for the smaller ones digit are brought back before the articles in a buffer line for a greater ones digit. Then secondary sorting is subsequently performed in which articles with the same tens digit are collected in the same buffer line.
This article rearranging device can rearrange the order of the articles so that the articles are arranged in the specified order. However, according to the method described in Patent Document 1, the articles which have been rearranged by the primary sorting and returned to the transporting line are arranged in groups of article each group of which consists of the articles having the same ones digit and which groups are arranged in the order that is in accordance with the values of their tens digits. And in the secondary sorting, the articles are distributed to each buffer line for group of articles based on the ones digits. Thus, it takes time for articles having numbers in sequence to be collected in each buffer line. And it takes time from the time the articles are received in the carrying-in area until the time they are taken out from the retrieval area.